1. Bacteria Discussion
September 19, 2018
(Really)

2. I. Prokaryotes Basic Characteristics Single celled
No membrane-bound organelles
Nucleoid region
Microscopic

3. B. How do we identify different types of prokaryotes?
Identified by the following:
Shapes
Chemical nature of their cell walls
The ways they move
The ways they obtain energy

4. C. Basic Structure Cell wall – protects the cell & gives it shape.
Outer membrane – protects the cell against some antibiotics (only present in some)

5. C. Basic Structure (cont.)
Cell membrane – regulates movement of materials into & out of the cell; contains enzymes important to cellular respiration.
Plasmid – circular piece of DNA that contains some genes obtained through genetic recombination.
Capsule & Slime layer – protect the cell & assist in attaching the cell to other surfaces.

6. II. Shapes & Groupings of bacteria
Three basic shapes of bacteria
Bacillus = rod shape
Coccus = round or spherical shape
Spirilla = spiral shape

7. B. Cell Groupings Diplo – cells are paired
Staphylo – cells are in grape- like clusters
Strepto – cells are in long chains

8. III. Cell wall types
Two different types of cell walls are found in eubacteria
Bacteria cells containing peptidoglycan
Bacteria with an outer layer of lipid and carbohydrate molecules
Gram staining helps to tell them apart using two different types of dye
Violet - primary stain
Red - counterstain

9. IV. Growth & Reproduction
Binary Fission: bacterium doubles in size, it replicates its DNA and divides in half
Each daughter cell is a clone of the parent
Is this sexual or asexual reproduction?
Asexual

10. IV. Growth & Reproduction (cont.)
Types of Genetic Recombination
Conjugation: process by which two living bacteria bind together and one bacterium transfers genetic information to the other
Transformation: occurs when bacterium binds to and then takes up DNA released by dead bacteria
Transduction: viruses carry portions of DNA from one bacterium to another

11. IV. Growth & Reproduction (cont.)
Endospore: thick-walled, dehydrated structures inside bacterium
Protects the cell against harsh environmental conditions, such as heat and drought
May allow the bacterium to survive for thousands of years
Not for reproduction, but for survival

12. V. Examples of Bacteria Bacillus cereus Found in soil Straight rods
Arranged singly or in pairs
Cause of a lot of food borne illnesses

13. V. Examples (cont.) Aquaspirillum serpens Found in fresh water
Spiral shaped
Arranged singly

14. V. Examples (cont.) Escherichia coli (E. Coli) Straight rods
Arranged singly or in pairs
Named after pediatrician who discovered it
Digest food in your intestines (benefit to us)
Some strains are very harmful and can lead to food borne illnesses

15. V. Examples (cont.) Staphylococcus epidermidis Staphylococcus aureus
Epidermis = skin
Spherical shape
In clusters
Usually not pathogenic
Staphylococcus aureus
Most common type of staph infections in humans
MRSA: Methicillin-resistant S. aureus
Highly resistant to antibiotics